This section provides background information related to the present disclosure which is not necessarily prior art.
Turbo machine systems represents systems for compressing a working fluid (for example: air) or increasing a flow rate by using turbo machines such as turbo compressors, turbo blowers, and turbo fans.
The conventional turbo machine has realized a high-speed rotation of a motor that rotates at a constant speed by using a speed increasing gear. However, in recent years, as bearing and inverter technologies have developed, a direct type high-speed rotation technology in which the turbo machine is directly connected to the motor is being applied.
However, although the turbo machine has the advantage of reducing the whole volume by the direct type high-speed rotation technology, cooling efficiency of a driving motor has a large part in overall efficiency of the turbo machine system.
FIG. 1 is a schematic view illustrating an example of a turbo machine system according to a related art.
Referring to FIG. 1, the turbo machine system according to the related art includes a driving unit for generating overall power, a compression unit for performing a series of operations such as intake, compression, and discharge of a working fluid by using the driving unit, a support unit for supporting the driving unit and the compressing unit to couple the driving unit to the compression unit, and a guide piping unit for guiding a flow of the working fluid.
The driving unit is provided with a motor constituted by a driving shaft (211), a rotor (212), and a stator (213) and is supported by the support unit including a casing (221) that surrounds the outside of the driving unit.
Since heat is mostly generated from the driving unit, in order to prevent the heat generated from the driving unit from being conducted to the compression unit, gaps (260a and 260b) are defined between the compression unit and the driving unit when assembled.
Meanwhile, in order to cool the driving unit, the casing (221) has a cooling fluid intake hole (241) that is defined in one side thereof to introduce the cooling fluid for cooling the driving unit and a cooling fluid discharge hole (242) that is defined in the other side thereof to discharge the cooling fluid that has cooled the inside of the driving unit.
Also, in order to improve cooling efficiency of the driving unit by using the cooling fluid suctioned into the casing (221), heat dissipation fins (214, 225a, 225b) are disposed on an outer circumferential surface of the stator (213) and outer circumferential surfaces of bearing housings (224a, 224b).
There is an example in which a cooling jacket for circulating coolant to dissipate the heat is disposed on the casing instead of the heat dissipation fins (214, 225a, 225b), or a fan for cooling is disposed.
The compression unit is provided with impellers (231a, 231b) rotated by the driving unit and impeller housing parts (233a, 234a, 233b, 234b) accommodating the impellers (231a, 231b) and having intake holes and discharge holes to guide the working fluid introduced into, compressed in, and discharged from the impellers (231a, 231b).
The compression unit may be symmetrically disposed on both sides of the driving unit as illustrated in FIG. 1 and may be disposed on only one side of the driving unit.
Meanwhile, the turbo machine system according to the related art discloses a piping structure for improving cooling efficiency of the driving unit, i.e., air circulation passages (236s, 236b) through which the cooling fluid discharge hole (242) of the driving unit communicates with the intake hole of the compression unit as illustrated in FIG. 1.
The cooling fluid discharged from the cooling fluid discharge hole (242) through the air circulation passages (236a, 236b) is guided to the intake hole of the compression unit. As a result, there is an advantage in controlling an amount of cooling fluid for cooling the driving unit according to a variation in rotation speed of the driving unit.
That is, when the driving unit increases in amount of heat generation due to an increase in rotation speed of the driving unit, the working fluid introduced into the intake hole of the compression unit increases in amount. Thus, an amount of cooling fluid for cooling the driving unit increases to activate the cooling of the driving unit. In a contrary case, the cooling fluid for cooling the driving unit may decrease in amount.
However, since the above-described turbo machine system according to the related art uses only the cooling fluid that is heated while the working fluid suctioned into the compression unit cools the driving unit, the compression unit may deteriorate in compression efficiency.